Rotating tool lathe



Oct. 12, 1948. E. D. BEACHLER v 2,451,147

ROTATING TOOL LATHE Filed April 21, 1944 10 Sheets-Sheet l E. D. BEACHLER ROTATING TOOL LATHE 10 Sheets-Sheet 2 Filed April 21, 1944 w Q m g 31 MM QM s f m @fl d Q Q in: m3 T Q m. T 1 & MM M1 m N KI. 1 RN I 15 Q \n% QQN 0 & 0 o wm f E m kw w Q nZ EZ Z 22 i on 1920 55405 452. QM fi OCt. 12, 1948. BEACHLER 2,451,147

ROTATING TOOL LATHE Filed April 21, 1944 10 Sheets-Sheet 3 Filed April 21, 1944 E. D. BEACHLER ROTATING TOOL LATHE 10 Sheets-Sheet 4 j CEHrEkL/NE 0F TOOL CENTEELIHE OF CRANE- SHAFT Z-ZTVETT c2? fbwmeo Q BEAC'l/L E2.

Oct. 12, 1948. E. D. BEACHLER 2,451,147

ROTATING TOOL LATHE Filed April 21, 1944 lo Sheets-Sheet 5 [aw lea 0. 55/90/1452.

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ROTATING TOOL LATHE Filed April 21, 1944 10 Sheets-Sheet 6 Iii E2 Z :2

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ROTATING TOOL LATHE Filed April 21, 1944 10 Sheets-Sheet 7 FEW :I c am/4290 D. BEACHLEE.

Oct. 12, 1948. E. D. BEACHLER ROTATING TOOL LATHE 10 Sheets-Sheet 8 Filed April 21, 1944 Oct. 12, 1948. BEACHLER 2,451,147

ROTATING TOOL LATHE Filed April 21, 1944 1o Sheets-Sheet 9 few/4 90 Q 554019.!6'2.

Oct 1948. E. D. BEACHLER 2,451,147

ROTATING TOOL LATHE Filed April 21, 1944 10 Sheets-Sheet 10' [an/flea 0. 5540/1452.

Patented Oct. 12, 1948 ROTATING TOOL LATHE Edward D. Beachler, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Application April 21, 1944, Serial No. 532,069

3 Claims. 1

This invention deals with machine tools of the rotating tool type and particularly relates to crank pin turning lathes.

In the copending application of Lloyd Hornbostel, Serial No. 530,371, filed April 10, 1944; entitled: Rotary tool lathe, and now Patent No. 2,426,932, granted Sept. 2, 1947, there is described a crank pin turning lathe having a longitudinally and transversely adjustable housing supporting a rotating lathe ring which receives a crank shaft therethrough and slidably supports tool carriages for feeding cutting tools to cut the heels, cheeks and crank pins of the crank shaft.

The present invention now provides electrical and mechanical refinements for machine tools such as crank pin turning lathes of the type disclosed in said Lloyd Hornbostel Patent No. 2,426,932.

According to the present invention, a main bed is provided with tracks supporting a carriage for longitudinal movement. The carriage is floated on films of oil on the tracks. The carriage, in turn, slidably supports the main lathe ring housing for transverse movement across the bed. This ring housing is also floated on oil films on the carriage. The carriage is moved longitudinally on the bed by a longitudinal feed screw driven at slow feeding speed through a differential gear arrangement from a rheostat-controlled motor and driven at fast speed, for setting up purposes, by a rapid traverse motor superimposed on the aforementioned feed motor through the differential mechanism. The main bed also carries stanchions for fixedly supporting the crank shaft or other work piece through the main lathe ring which is rotatably mounted in the lathe ring housing. Additional standards can also be mounted on the bed outwardly from the stanchions to carry the extending ends of the crank shaft. The bed can be equipped with extensions cn both ends thereof which cooperate with the tracks on the main bed itself so that the stanchions and the standards can be moved along the entire length of the bed. This arrangement makes it possible for the machine to act on crank shafts of any length since the extensions on the bed will accommodate positioning of the stands at proper intervals along the length of the crank shaft to accurately hold the shaft in position while it is being cut by the tools. In order to maintain a constant relative speed between the cutting tools and the crank shaft or other work piece, the machine of this invention has an automatic speed up arrangement which increases the rate of rotation of the main lathe ring as the cutting tools move inwardly toward the center of rotation and thereby act on sur faces spaced at smaller radial distances from the axial center line of the work. Iliis automatic arrangement provides constant linear speed relationship between the tool and the surface acted on by the tool. In addition, the machines of this invention have automatic speed up devices which increase the speed of rotation of the main lathe ring whenever the tools are out of active engagement with the work, or are cutting air. In the cutting of the heels and checks of crank shafts, the cutting tools are only in engagement with the heel and cheek surfaces for a relatively small increment of each complete rotation thereof, so that they are not effective for the major portion of each rotation. According to this invention, the time for heel and cheek turning operations is materially decreased by speeding up the tools much beyond an optimum cutting speed whenever they are out of contact with the Work and then slowing the tools down to an optimum cutting speed when they contact the work.'

It is, then, an object of this invention to provide machine tools accommodating work pieces of any length and capable of acting on such work pieces at any portion along the length thereof.

A further object of the invention is to provide a rotary tool lathe adapted to accurately lathefinish the heels, cheeks, and pins of crank shafts within tolerance limits never heretofore attained, and at speeds heretofore considered impossible.

A still further object of the invention is to provide a crank shaft-turning lathe with a bed arranged to receive extensions accommodating crank shaft-holding standards at any portion along the length so that the machine will accurately hold and lathe-turn crank shafts of any length.

A still further object of the invention is to provide a crank pin-turning lathe with a bed accurately holding a carriage for longitudinal movement on films of oil.

A further object of this invention is to provide a longitudinal feed arrangement for the main lathe ring of a rotary tool lathe which accurately advances the lathe ring relative to the work at a desired speed and which can readil be driven at greatly increased speeds for setting purposes without affecting the selected feed speed.

A still further object of the invention is to provide a rotary tool lathe with a longitudinal feed screw drive on which is superimposed a 3 7 rapid traverse speed drive to quickly set up th machine for use.

A still further object of the invention is to provide electrical controls for a crank pin-turning lathe which automatically increase the speed of rotation of the lathe as the tools feed inwardly toward center of rotation.

Another object of the invention is to provide a rotary tool lathe which maintains a constant speed relationship between the lathe tool and the work surface acted on by the tool.

A still further object of the invention is to provide an automatic electric .cqntrol device for crank pin-turning lathes .which speeds up the rotation of the lathe whenever the lathe tool is out of contact with the crank shaft.

A still further object of the invention is'to provide electric control means for rotary tool lathes which automatically increase the speed of rotation of the tool beyond an optimum cuttin tool speed when the tool is out of contact with the work, and then automatically slow down the tool .to an optimum cutting tool speed as it approaches the work while mainta nin h s D.- timuin speed throughout the duration of contact of the .tool with the work.

A further object of this invention is to provide a crank pin-turning lathe which materially vdecreases the time consumed for finishing the pins,

heels, and cheeks of. crank shafts.

Another object of the invention is to provide a crank pin-turning lathe with an electric inching device whi ch positions the tool relative to the work. V

A still further object of the invention is the provision of" a crank pin-turning lathe carriage assent 1y floated on oil and adapted to be manually moved with ease by an operator so that it can be quickly set up in position for use.

'(Dther'and further objects of this invention will become apparent to those skilled in the art from the following detailed descriptions of the anh s sl sheets. of hav n h c by a ef ferre essmele eels. illust a e e e m me ei eihveht hi 9h he aw n a top plan view of the crank pin- Figure 1 is turnin lathe: V

Fi ure 2 is s devetiehel v e of Fi ure iellre s e re. t Le e evat onal w a m u e 1 s e o e ser sealeit est d elevati nal ie o e 1 see! 2 on s er i ure. is a f a me tar nla ged hse erosss tienal View, wi h arts i e e t on. and wi h Pe em t d; take shes th line .e'f sie 1 F ur 6. is s a men a y ar d i evatiorial view, with parts broken away and shown in vertical cross section, and taken along the line Vi w 9 Figure .1 i

sens i s h e ee r ement r an v taken along the line Ill-5X71; of Figure 2 and llu tratin thse i s h a ar e e l t n ho n F ure 2 Figure ihse sressei ene w t rts d e evat on. t ke l n he l n I.V ef 1-.

Figure 9 is a transverse vertical cross-sectional rangement for floating the carriage on films of oil.

Figure 11 is a vertical cross-sectional view taken along the line XI-XI of Figure '7 and illustrating the differential drive for the longitudinal feed screw on a larger scale.

hisir 1 i a some hat i rammat s .drive assembly for rotating the main lathe ring at controlled selected speeds and for sliding the tool carriages relative to the main lathe ring.

Figure 13 is a wiring diagram for the main lathe ring and tool carriage drive.

Figure 14 is an end elevational view ofa crank shaft adapted to be lathe-turned by the crank pin-lathe of this invention.

Figure 1 5 is a fragmentary side elevational view of the crank shaft of Figure 14.

. Figure 16 is a cross-sectional View taken along v V the line XVIXVI of Figure illustrating the View: with parts in' elevationitaken along the X IX e i u 7- ria agrammati'cally illustrating the lubrication are i s he 'eie she ew f the w e t e a n l the' ihe e h e d. di-

crankshaft with the heels finished in accordance w th th hv h ie As shown on the drawings:

h ma ine in n r As shown in Figures 1 to 4, the machine includes a main bed ill with extensions H, H on the front and rear ends thereof. A main carriage :3 is longitudinally slidable n the main bed it. A main lathe ring housing I 3, is slidable' Q on the carriage l2 transversely of the bed 10.

Work-supporting stanchions I4, 14 are slidable on the main bed II} on opposite sides of the housing l3. Work-supporting standards l5, l5 are slidably mounted on the bed extensions I l, -l I As best shown in FiguresB to 5, the ring housing 13 has a back wall l3a with a circular aperture [32; therein together with a front wall defining a larger circular aperture I30. 7

The main lathe ring 15 is rotataloly mounted in the housing is and has. a flat front face Ilia fittin in the aperture I to ether with a cen- 't'ral hollow hub portion lfib extending into the aperture I550. The hub [51) has an outer peripheral cylindrical face 1 60. A main bearing ring IT is carried by the bad, Wall l3t4 of the housing i3 and has an inner peripheralwall 11a receiving the face I of the hub. in rotatable relation thereo I add ion. the. rin H. h s s e aces H12. H 2 proi e he n o the apertu e 31 o th housing with one vface thrusting against a shQul der lid. of the athe h l and the oppos d c hrustin a ains a ad stable t st ri g 1. a r b the hub Ni Adju ta e shoes such a H! se etween the oute p riphery of the h n and a tapered We l. portion we of the:

the rin 61 9 ,hQlQ- th hub a l. 15. on h h a ng wan 1 .1;

sea in 210 f. ubb fe t or the l e. is mbe ded. h the. bac we Beef t e us ar und. th rzeriphe v B1? t cors w th a ea plat 2. a ie y the hrust has t or sealin the ap betwee t is hru t r n and t e wa definin he im e-rlv a eal rin the ma hine as shewn in F res 3 and h st ak sha 2.5 has m n he in s 25stv connect ing rod be'arings or crank pins. 25b, and webs 25c connecting the bearings 25a and pins 25b. The bearings 25a adjacent the pin or web portion being acted on by the lathe are clamped in the stanchions, M, It on the front and back sides of the housing l3 while the extended portions of the crank shaft can have remote bearings 25a thereof resting on the standards l5, 15. Each standard l5 has a vertically adjustable head a that can be raised and lowered by means of a screw jack l5?) so that it will be readily moved into supporting position.

Each stanchion l4; M has a head carrying removable blocks Ma in angular relationship for seating a bearing a. These blocks Ma are replaceable and are provided in sets of varying heights so that the crank shaft will be blocked up at the exact level desired for the turning operation. The heads of the stanchions l4 carry swing bolts lb on which are slidably mounted a cap member Mo also carrying blocks Ma. Nuts on the swing bolts Mb can act on the cap Mo to draw the cap toward the head of the stanchion and tightly clamp the bearing for holding the crank shaft in rigid fixed position through the lathe ring aperture 561. It will be noted from Figures 1 and 2 that the stanchions l4, M are movable on the bed If to position the clamping heads close to the aperture 26] of the lathe ring if desired, so that they can grip portions of the crank shaft immediately adjacent the portion being acted on by the lathe tools.

As shown in Figures 3 and 5, the front face I 6a of the lathe ring l6 has parallel ways or gibs 26, 26 on diametrically opposed sides of the aperture 16). Thes ways 26 are of dovetail cross section. Tool carriages 27, 2'! have base legs 21a, 27a. with dove-tail grooves 21b, 21b therein slidably mounted on the ways 26, 25. Each tool carriage 21 has a main leg 21c extending from one end of the base leg 27a in right-angular relationship therewith. The tool carriages 2? are thus of L-shaped configuration. The free end of the main leg We of each tool carriage is bifurcated as at 27d and this bifurcated end slides on a track 28 opposing the gib or way 26 so that the tool carriage will be mounted for steady accurate movement toward and away from the center of the lathe ring. The main leg 270 of each tool carriage, as best shown in Figure 3, has inwardly projecting tool-clamping jaws 29 receiving therebetween a tool holder carrying a lathe tool 3!. The lathe tools 3! are in diametrically opposed relationship and are fed toward and away from each other by movement of the tool carriages 21 on the ways 25 and tracks 28.

Tool carriage feed screws 32 have threaded relationship with nuts 33 removably carried by the carriages 2? for sliding the carriages on the tracks and ways. The feed screws 32 project into transmission housings 34 carried on the face Go of the main lathe ring. As will be hereinafter more fully described, these housings 34 contain worm and worm wheel drives.

As shown in Figures 3 and 4 the main ring housing 13 has laterally projecting portions 35 and 36 on the sides thereof. As will be hereinafter more specifically described, the portion 35 provides a gear casing as shown in Figure 6, while the portion 3'5 provides a cabinet for electrical equipment.

As shown in Figures 1 to 4, a platform P1 extends around the front side of the casing 35 and ring housing E3 to register with a platform P2 extending along the front end of the ring housing from adjacent the rear side of the machine and a platform P3 extending along the rear end of the housing from the rear side of the machine. The platform P1 has a stairway S1 dependng therefrom into spaced relation from the floor. The platform P2 has a similar dependent stairway S2 while the platform P3 has the same type of dependent stairway S3. The platforms and their dependent stairways are all carried by the ring housing structure, and are movable therewith along the bed H]. The platforms give ready access to all of the operating controls of the machine and facilitate inspection of the latheturning operation.

From the above descriptions it will be understood that the machine has an elongated bed on which a carriage is slidably mounted carrying a housing assembly in transverse movable relation thereon. This housing assembly supports the main lathe ring receiving the work therethrough. The lathe ring carries one or more tool carriages which are fed radially inward or outward, as desired. The bed also slidably supports workclarnping stanchions on opposite sides of the ring housing together with work-supporting standards for carrying extended end portions of the work.

Work done by the machine The crank pin-turning lathes of this invention cut, to accuracies not heretofore obtainable, the crank pin, the inside faces or cheeks of the webs between the pin and the main bearing, and the heels of the webs adjacent the main bearings, of crank shafts. These operations cannot be satisfactorily carried out on a conventional workrotating lathe since, in such lathes, it is necessary to rotate the crank shaft about the center line of the pin being machined, and a lathe with an exceptionally large diameter swing would thus be required. Since crank shafts for marine engines and large stationary engines may have crank pins of several feet in diameter and a throw of 24 inches or more, it is apparent that the swing required for turning such large crank shafts on work-rotating lathes would be too large to be practicable. In addition, since the crank shafts must be rotated 01f center in a conventional lathe, a clumsy arrangement necessitating the use of counterweights and a special steady rest is required.

The crank pin-turning lathe of this invention avoids the problems encountered with the turning of crank pins in conventional rotary work lathes by holding the crank shaft stationary and rotating one or more cutting tools around the crank shaft. The machines of this invention are easily set up to accommodate crank shafts of widely varying size ranges, and will machine the crank shaft in onehalf to one-fourth the time heretofore required while carrying out this rapid machining at tolerances within .001 inch, even on the largest size crank shafts.

In Figure 14 a rough crank shaft 25 is illustrated in end elevation. This shaft is initially formed from a forged billet that has slugs cut therefrom at spaced intervals along the length thereof and is twisted to position the crank pin-forming portions at the desired angular relationship around the main bearings. As shown in Figure 14, the crank shaft blank or starting work piece for the machines of this invention has main bearings 25a which have been lathe-turned to finished dimensions in a conventional rotating work lathe, since this turning operation is performed while rotating the work about its axial center. Webs 25c radiate in angular relationship from the main -bearings 25d and carry the crank pins at their outer ends. The edges of the webs 251) have heels 25d which can also be finish-turned on the rotating work lathe, since they are equidistant from the axial center of the crank shaft. The inner ends of the webs, however, cannot have the heels thereof finish-turned on the conventional lathe without mounting the shaft in off-center position as described hereinabove. Therefore, the starting blank does not have the heels on the inner ends of the webs adjacent the main bearing 25d finished, nor does it have the checks or inner faces of these webs finished. Likewise, the crank pins themselves are not finished.

As shown in Figure 15, the crank shaft 25 has the crank pin 25b, the cheeks 256', and the heels 25f by the crank pin lathe of this invention. These turning operations are finished to tolerances of even less than .001 inch in one-half to one-fourth the time heretofore required, and

crank shafts of tremendous size can be accommodated because they are held stationary during these operations. Crank shafts from sixty to eighty feet in length and having crank pins two to three feet in diameter can be handled with ease.

As shown in Figures 3 and 4, the 'stanchions l4, l4 securely clamp the main bearing portions 25a, 250. on each side of the crank pin 25b and web 250 to be acted on by the machine. Since the ring housing [3 can be transversely moved on itssupporting carriage l2, it is immaterial that the crank pin 25?) to be acted on is off-center from the supporting stanchions, since the housing can be so positioned that the center of the crank pin will coincide with the center of the housing.

As indicated in Figure 15, the inside cheeks 25c of the webs 252) are readily finished-turned to accurate tolerances. The inside heels 25 are similarly finish-turned.

The machine bed construction As best shown in Figures 1, 7 and 9, the main bed Hi has relatively wide flat-top tracks llla, Ida on the front andrear sides thereof. A flattopped track ldb is also provided on this main bed ii! in spaced parallel relation from the front side of the machine. This track 10b extendsbeyond the ends of the tracks lila. A pair of closely spaced paralled tracks we having narrower flat tops is provided adjacent the rear side tracks Ida in spaced parallel relation therewith and extending longitudinally beyond the ends of this rear side track Illa to terminate flush with the track a All of the tracks are in integral relationship, being connected by webs d of the main bedas best shown in Figure 9.

The end beds ll, I I, as best shown in Figure 1,

each have a track l lb aligned with the track lllb of the main bed and spaced parallel tracks llc aligned with the spaced parallel tracks We of the main bed. The end beds H, H are bolted, or otherwise secured to the ends of the main bed It to position their tracks 1 id and He in aligned relationship with the tracks 56b and Hlc of the main bed. i

As best shown in Figure 9, the main carriage 12 has flat pads ifia. lzdri'ding on the tracks lila, ifla of the main bed, a pad I2'b ridingon the track [01), and spaced parallel pads I riding on the tracks Ito.

Strips 3'5, 31 are bolted ontothe carriage m to underlie the pads lZa, 112a and ride under the tracks lea, ma forholding the carriage. down on the tracks. Ribs |2e, lie. depend from the 'pad I?!) and the inner pad l2c to act on strips 31a inserted between the ribs and pad I01) and inner pad Idc to hold the carriage against. sidewise movement on the bed.

As shown in Figures 3 and 4, the standards' l5, I5 likewise slide on the tracks lib and Me of the. end beds H, H. These standards l5 have bottom pads resting on the tracks together with attached end strips 38 riding under the outer tracks ill and He for holding the standards down on the tracks. In order to prevent cocking of the standards, a portion |5d on the bottom of each standard extends between the tracks I [0.

A rack 39 is'provided along the length of the inner track Ho adapted to be engaged by a spur gear 40 on a spindle 4| rotatably carried in the bottom wall of the standard l5. The spindle 4| can be engaged by an operating handle to rotate it for rotating the spur 40 and thus effecting longitudinal shifting of the standard.

The stanchions it are similarly mounted and similarly equipped with spur gears and rotating spindles for shifting the same. Both the standards and the stanchicns can ride on either the tracks tilt) and lilo of the main bed ill, or the transversely over the carriage I2. From the above description it will be understood that the bed for the machine of thi invention has a plurality of tracks thereon slidably supporting the main carriage for the lathe ring housing as Well as the supporting and clamping stanchions for the crank shaft.

The longitudinal drive As best shown in Figures 1, '7 and S an elongated screw rod .40 is rotatably mounted at one end in a bearing il secured on a cross strap of the main bed it and i rotatably mounted inthe other end in a combined bearing and coupling 42 carried by a cross strap or pad of the main frame. A drive shaft 43 from a differential 44 connects the screw All with the differential mech- 3 anism. This differential mechanism. is driven by two motors t5 and Miss will be hereinafter more specifically described. a r

The rod 4B is threaded through a casing 41 having an elongated nut ila (Figure 8) rotatably journaled therein. The casing 411 depends from the carriage i2 and rotation of the screw rod is .rnoves the nut d'ia along the length therethis enlarged casing portion 'd'lh by being secured to nut fild. Worm wheel 43 is engaged by aworm 49 mounted in bearings miscarried by the casing and coupled to a shaft 5.! extending through an aperture in the carriage 12 into a gear housing 52 on a pedestal 53 bolted to the bottom of a groove 12d on the top face of the car-ria'ge l2. The ring housing I3 has a rectangularap erture the casing '4'! has a 54 in the base portion ltd thereof riding in this groove I211. The aperture has it long axis transversely of the main bed it as shown in Figure '7.

The ring housing l3 has a transverse box-like portion 55 (Figure 5) extending across the rear face thereof at a level beneath the ring aperture, and this box has an open bottom 5511 through which project the gear housing 52 and pedestal As shown in Figure 9, the upper end of the worm shaft 5! has a bevel gear 55 secured thereon in the gear housing 52. Thi bevel gear 55 meshes with a bevel gear 5? at right angles thereto which is slidably keyed on a transverse shaft 58 slidably projecting through a bearing 59 carried by a side wall of the housing 52. An elongated key 53a is secured along a portion of the length of the shaft inwardly from the end of the shaft. The housing 52 has a tubular extension 5211 on the sid: wall thereof opposite the wall carrying the bearing 59, and this tubular extension 5211 is adapted to receive the end of the shaft 58.

The shaft 58 extends through the housing 55 into the casing 35 on the front side of the ring housing as shown in Figure 6. As therein indicated, the shaft 58 is near the bottom of the casing 35 rotatably supported on a bracket 53 and having a bevel gear 61 secured to the end thereof. The bevel gear 6! meshes with a bevel gear 62 in right-angular relation thereto. The gear E2 is on the bottom of a vertical shaft 83 extending upwardly in the casing 35. The upper end of the shaft 63 has another bevel gear 64 thereon meshing with a bevel gear 55 keyed to a horizontal shaft 66 rotatably mounted in the casing. This shaft 66 has a gear 87 on the end thereof meshing with a gear 68 loosely disposed around another horizontal shaft 69 but secured to a hub '50 of a hand wheel 'H on the front end face of the casing. A similar hand wheel TI i provided on the rear end face of the casing and its hub is geared to the shaft 65 in the same manner as just described.

Rotation of either hand wheel ll will rotate a gear- 68 meshing with the gear 5'! on the shaft 65 to rotate the shaft 63 through the bevel gears 64 and 55. The shaft 63, in turn, rotates the shaft 58 through the bevel gears 6! and 62, and this shaft 58, as shown in Figure 9, when rotated, causes the key 58a thereon to drive the bevel gear 5? thereby rotating the gear 55 and worm shaft 55 to drive the worm 39 and rotate the worm wheel 22. Since the worm wheel a3 is effectively threaded on the screw rod 59 but is held against free lateral movement in the casing 47, and since this casing 4? depends from and is secured to the carriage i 2, the carriage will be moved longitudinally on the main bed 19. When rod 49 is rotated by drive shaft 43, the nut 47a is held against rotation by worm 48, hence movement of casing i'l along the main bed again results.

From the above description, it therefore will be clear that rotation of either hand wheel ii will cause longitudinal shifting of the carriage l2 and the ring housing on the carriage. As will be hereinafter more fully described, this heavy assembly can actually be moved by manual effort since the lubrication system so materially re duces friction that many tons can actually he slid on the main bed with a very small manual pull on a hand Wheel.

The above-described manual longitudinal shifting of the carriage and main ring housing is brought about when the longitudinal feed screw 40 is at rest. This manual shifting is generally only used for slight adjustments of the longitudinal position of the cutting tools carried by the lathe ring. Longitudinal feeding of these cutting tools during the lathe-turning operation is effected by rotation of the feed screw 40 by driving the shaft 43 coupled to the feed screw with the differential mechanism 44. During rotation of the feed screw 40 the worm wheel 48 is not rotated, since the worm 49 holds it against rotation and the rod 40 merely turns through the stationary wheel. Thus, during driving of the feed screw, the hand wheels H are not driven.

As shown in Figures 1, '7 and 8, the differential mechanism 44 is mounted between the track lllb and the inner track I00 of the main bed [0 toward the front end of the bed.

As shown in Figure 11, the differential mechanism 44 comprises a main casing 12 with a removable cover 72a thereon, a cap 12b secured to the front wall thereof, and a cap 120 secured to the rear wall thereof. A main differential shaft '13 is rotatably mounted in the casing 12 on end bearings 74 and 15. The end bearing 14 is carried in a boss portion of the head cap 12b while the bearing 15 is carried in the cap 120.-

Bearings 16 and I! carry a hub member 18 freely around the shaft'13 adjacent the bearing 14 while bearings 19 and carry a second hub member 8i freely around the shaft 13 adjacent the bearing T5. The hub member 18 has bevel gear teeth 18a on the rear end thereof while the hub member 8! has bevel gear teeth Bla on the front end thereof in spaced opposed relation to the teeth 78a. The teeth 18a and Bla respectively mesh with differential gears 82 carried from the legs 83a of a spider 83 on bearings 84. The spider 83 is keyed to the shaft 13 by means of a key 85 between the bearings 11 and 19.

A. worm wheel 85 is bolted to the front end of the hub 18 and meshes with a self-locking flat angle worm 86 on a shaft 81 coupled to the electric motor 45.

The rear end of the hub 8| has a worm wheel 88 bolted thereon meshed with a multl-thread or steep worm 89 on a shaft 90 coupled to the motor 46. This motor 46 is equipped with an automatic brake (not shown) which looks the shaft 98 whenever the motor is deenergized so that the worm 89 will prevent the worm wheel 88 and hub 81 from rotating.

The casing 12 has a sump 12d in the bottom thereof for containing lubricating oil. A pump BI is bolted on the front cap 121) and has an inlet 9la receiving oil from the sump 12d together with an outlet 9Ib discharging into a duct 92 in the cap 12b. This duct 92 can be drilled in the cap and it is closed at its bottom end by means of a plug 93 and communicates at its upper end with a tube 94 fitting freely into a longitudinal bore 13a through the differential shaft 13. The duct 92 also communicates with a pressure gauge 95 threated in the cap 12b.

Bleeder passages 13?) lead from the longitudinal bore 13 at intervals along the length of the bore to bleed lubricant to the bearings and gears in the casing. The rear end bearing 15 is protected with. a seal 15a bolted on the cap 12 and having close-running clearance with the projecting portion of the differential shaft 13.

The pump 9| will force lubricant through the tube 94 into the longitudinal bore 13a. Some of the lubricant will bleed out of the front end of this bore to lubricate the bearing 14 while additional lubricant will bleed through the bleeder ii passageways 73b to lubricate the bearings and gears. The lubricant after passing over the gears and bearings is again collected in the sump 12d for recirculation.

Rotation of the worm 85 by the motor 45 when the worm 89 is looked, as when the motor 46 is dee'nergized and the brake thereon applied, will cause'rotation of the hub 18 and rotation of this hub will tend to rotate the differential gears 82 because of the meshed relationship therewith. However; the hub Si is held against rotation by the worm- 89 and will prevent rotation of the difierential gears 82. Therefore, the hub 18 will drive the spider 83 to cause rotation of the differential shaft 73 at a speed determined solely by the speed of the motor 35. Rotation of the shaft 1%,oi course, drives the coupling shaft 43 and the screw ro'd' fill to effect longitudinal sliding of the carriage E2 on the main bed iii thereby controlling the longitudinal feedof the lathe tools.

The motor is a D. C. motor energized by the generator of'a motor-generator set. The speed of the motor 45 is controlled by variation of resistance in its field as by means of a rheostat 96' (Figure 6) in the upper end of the casing of the main ring housing and by variation of resistance in the field of the energizing generator by means of a second rheostat 99. The rheostat arm 56a is secured on a shaft 91 controlled by a manually-operated knob 98 on the front end face of the casing. The second rheostat 99 has the arm 99 a thereof on the same shaft 91 but arranged so that the resistance will be successively applied to the two fields. A wide speed range for motor '45 is thus obtained.

The motor 46 is an A. C. constant speed motor for rapid traverse driving. Driving-of the motor 46 will rotate the hub 8! thereby tending to rotate the differential gears 82; However, if the motor 55 is stationary, the hub 1-8 will be locked and the gears 82 cannot rotate. In such cases, the motor 46 will be effective to drive the spider 83. This rapid traverse motor 46 is used for initial positioning of the-carriage along the length of the bed, as when setting up the machine for use; In such cases, it is desirable to move the ring housing to approximately its operating position as rapidly as possible. Then themanualcontrolled hand wheels H can be used to gently movethe ring housing into its exact desired longi- F tudinal position.

During the lathe-turning operation, the motor.

1 5 alone drives the longitudinal feed screw 40 at a selected rate, determined by the settings of the rheostats 96 and 99, for advancing the tools longitudinally.

The rapid traverse motor 46 can be driven when the" feed motor is operating to cause an additive driving effect on the differential shaft 13 so that rapid longitudinal shifting can occur between the slow feeding operations. If one motor is driven in a direction opposite to the direction of the other driving motor, the feed screw will be driven at a speed equivalent to the differences in speeds of the motors and in the direction determined by'the faster motor.

The control knob 98 is thus effective to maintain exact longitudinal feed speeds for the feed screw and the rapid traverse motor 46 can be superimposed on the motor 65 or can be driven alone for the initial setting of the longitudinal position of the ring housing. A very wide range of operating speeds is obtained.

From the above descriptions it will be understood that the longitudinal drive of the lathe .12 includes both a motor drive and a manual drive. The motor drive has a. driving motor, a rapid traverse motor, and a differential gear assembly driven by either one or both of the motors. The controls for the motor drive and the manual drive are conveniently located on the same gear casing 35. 1

The transverse positioning mechanisms As explained hereinabove, the base of the ring housing i3 slides on the top of the carriage l2, and has ways or gibs lfid projecting into complementary grooves i201 in the carriage l2. In order to initially position the ring housing 23 relative to the work so that the lathe ring it will rotate about the desired center, the carriage i2, as shown in Figures 2, 3 and i, has a. gear housing tilt secured thereon. The housing I013 contains a worm wheel on a shaft it?! (Figure 9) threaded through a nut I82 depending from the base of the ring housing 53. A worm (not shown) on a shaft ass (Figures 2 and 3) meshes with thewheel in the casing I00 and a hand wheel Hi4 is secured oncne end of this shaft m3 for manual rotation of the worm to rotate the shaft Iii! and cause the ring housing IE to slide on the carriage it. A rapid traverse motor N35 is coupled to the other end of the shaft N53 and can be energized to drive the worm me'- 7 by a scale I66 on the ring housing base, and a pointer H3! on the front end of the carriage l2.

Quick and accurate transverse setting of the ring housing on the carriage can be accomplished by providing a bracket I98 on the ring housing base with a stop lfiiia axially aligned with an opposed stop lllla onthe finger. A rod exactly equal in length to the desired distance for displacing the center of the lathe ring I5, from the axial center of the bed is then inserted between the two stops iiiila and Mia and the hand wheel HM or the motor N15 is manipulated until this rod just snugly fits between the stops. If a rod of the desired length is not available, as, for example, when setting the machine to accommodate an unusual type of work piece, a second stop llllb on the finger I0! acts through a sliding rod I09 carried in brackets HG on the carriage I? to actuate the accurate dial gauge H5 also carried on the bracket I08. This dial gauge Hi can cooperate with the scale i536 to give micrometer readings.

From the above descriptions it wil be understood that the rapid traverse motor lilii and a hand wheel m4 selectively rotate a shaft M3 for driving a worm and worm wheel to actuate a screw rod for positioning the ring housing transversely on the carriage. This transverse'setting must be ver accurate since it determines the center about which the lathe tools operate and a gauge assembly is provided on the carriage and ring housing base to indicate the exact transverse setting of the ring housing.

The lubrication system I04 thereon has dependent brackets II2 providing a platform I I3 for a lubricator H4 and an electric motor I I5 for driving this lubricator. The lubricator H4 is of the positive pressure plunger type and has a hand crank I Ma on the front face thereof for manually actuating the same in the event it is desired to pump lubricant without operating the motor I I 5.

As best shown in Figure 10, the motor H5 drives the lubricator I It through reduction gears in a casing IIEa. A timer is also provided (not shown) for stopping driving of the motor I I 5 after a predetermined period so that the lubricator I I5 will not flood the lubricated surfaces. A plurality of oil tubes H5 extend from the lubricator I I4 to various parts of the carriage I2. The pads I2a, I22), and I20 of the carriage have lubricant-distributing grooves I I! therein arranged in reverse diagonal fashion along the length of the pads and opening onto the bed tracks on which the pads ride as hereinabove described for distributing lubricant to the tracks. As shown, each groove II! has a connection Illa with a lubricant-conveying tube I I 5.

Some of the tubes terminate at the center of the carriage as at II3 to drip oil onto the longitudinal feed screw 48. Other tubes I it terminate as at II9 to drip oil into the nut gear casing or box 47. A tube H6 is positioned as at I23 to drip oil onto the transversing nut M2 for moving a the ring housing I3. Other tubes are positioned as at I2I to supply oil to the ribs I26. Other tubes are positioned as at I22 to lubricate the strips 3?.

This oiling arrangement provides for the actual floating of the carriage I2 on films of oil on the bed so that movement of the carriage is readily effected with only very little frictional resistance, and an assembly weighing as much as thirty to fifty tons can actually be shifted by manual movement of the hand wheel I I.

The grooves lid on top of the carriage likewise receive lubricant from the tubes lit to lubricate the gibs or ways itd for facilitating transverse movement of the ring housing I3. The tubes I23 can feed these grooves I2cZ as at I23 (Figure 10).

The lubrication of the main bed for easy movement of the carriage I2 is effected automatically whenever the rapid traverse motor 46 is running since the motor H5 will be started at the same time. However, a timer (not shown) is provided so that the lubrication will continue for at least a predetermined period even though the rapid traverse motor stops short of that period. This insures sufiicient oiling and prevents flooding of the lubricated surfaces. The oil from the lubricator H4- is not recirculated since it is of an adhering nature tending to remain on the ways and tracks to float the carriage and housing on films of oil, and only small amounts of oil are necessary.

The oil lubricator is not operated throughout the longitudinal feeding stroke as when the motor G5 only is running since this motor only drives at slow feed speeds and suflicient oil is provided from the rapid traverse operations to last through the feeding operations.

In order to keep the ways and tracks clean and at the same time to seal the oil film between the sliding surfaces, felt seals I2 3 (Figure 3) are pro vided on the carriage to rub on the tracks. Similar felt seals I 24 can be provided on the leading ends of other lubricated parts such as on the end faces of the ring housing base.

As shown in Figure 5, the ring housing I3 has an oil reservoir-defining portion -I 25 communicating as at I25a with the main lathe ring. The main lathe ring is lubricated through tubing dischargin into the ring housing I3 and an oil pump I25 (Figure 3) driven by another electric motor I21 (Figure 4) is provided for forcing lubricant into the ring housing through these tubes. excess oil drains into the reservoir I 25 and is returned. for recirculation to the pump.

From the above descriptions it will be understood that the lathe ring parts are lubricated by an oil system which includes recirculation of oil by an electric motor-driven oil pump. The longitudinal movement of the carriage on the main bed, and the transverse movement of the ring housing on the carriage are facilitated by another lubrication system which does not involve recirculation of oil and which utilizes a separate motor and a plunger type lubricator.

The gear drives for the lathe ring and tool carriages As shown in Figure 5, the lathe ring It has a main ring gear I21 secured thereon around the inside face thereof near the outer periphery. This ring gear I2! is fixed to the lathe ring It by bolts or other securing devices (Figure 12).

The lathe ring It has a cylindrical wall or pilot portion I28 therearound radially inward of the ring gear I21. A second ring gear I29 is rotatably mounted on this pilot portion I28 and is held thereon by means of plates such as I33. This second ring gear I29 ha a double row of teeth IZQa and I291) therearound.

As shown in Figures 1, 2 and 4, a large motor I3I is mounted on the rear end face of the casing 35. This motor drives the main lathe rin I 6. As shown in Figure 12, the motor iSI drives gear I32 meshing with a gear i353 on a shaft I3 3, This shaft I34 has a gear 535 thereon driving a gear I36 on a shaft I337. The shaft I37 carries a gear 538 meshing with the ring gear 2? for driving the ring gear.

The shaft I 31 also drives a second gear I3 meshing with a gear M l having a hub MI rotatably mounted on bearings I 32 disposed around a differential shaft I 43. Thi difierential shaft has a spider M l keyed thereon rotatably porting differential gears M5 on bearing M5. The shaft I 53 also has a second set of bearings I4! thereon r'otatably supporting the hub I48 of a second gear I43. This gear I 29 meshes with the teeth I290. of the rotatably mounted ring gear I29 on the pilot portion I28 of the main lathe ring I6. The teeth I29b of thi same ring gear I29 mesh with a gear I59 clutch keyed as at 55th; on a stub shaft I55 which is rotatably mounted in the casing 38 bolted on the front fac of the lathe ring I 5. A worm i5? is disposed in this casing 34 keyed on the shaft I5! and meshes with a worm wheel I53 for driving the tool carriage feed screw 32.

The gear I 45 driven by the gear I39 from the drive shaft I 37 has gear teeth on its hub I M meshed with the differential gears Idii to rotate these gears on the spider 5%. However, the hub I68 of the gear M9 also has m shed engagement with the same differential gears Idf, and if the differential shaft 53 is held stationary the differential gears will rotate on the spider I45 to drive the hub I48 and gear 5% in a direction opposite to the direction of rotation of gear 538 but in the same direction as the direction of rotation of the gear I38 driving the ring gear I2'I, The gear M9 will thus rotate the ring gear I29 in the The same direction as the ring gear I21 and the gear ratio is such that no relative rotation occurs between gears I21 and IE9. With ring I29 rotating in the same direction and at the same speed as ring 121, gear I58 is not-driven and the tool carriages do not move.

While the motor I3I is effective to drive the tool carriage feed screws 32 as well as the main lathe ring, as explained the lathe ring can be driven and the feed screws will not be driven unless the shaft M3 is rotated. For this purpose, a gear I54 is keyed on the differential shaft I43 and a gear I55 meshes with the gear IBII.

The I55 drives a shaft I55 on which a plurality of gears I51 are slidably keyed. The gears I51 selectively mesh with gears I53 on a shaft I59 and these gears I53, in turn, selectively mesh with sliding gears I68 on another shaft I6I. The shaft 'I'IiI drives sliding gear-s I52 on a shaft I63.

As shown in Figure 3,gear shifting rods A, B, and C are provided for selectively sliding the gears I51, I60, and I62 on their respective shafts to drive the shaft I63 from the shaft I56 at any one of a large number of speed ratios. A gear shift arrangement is thus provided which can be selected by relative positions of the shifting levers A, Band C to give a wide selection of speed ratios between the shafts I56 and I63.

The shaft I63 drives a reversing clutch I 64 containing opposed bevel gears I65 and IE adapted to be selectively driven by a shiftable member I61 slidably keyed on the shaft I63 or a shaft coupled with the shaft I63. The bevel gears I65 and I66 both mesh with a common bevel gear I68 keyed to the shaft I66. 7

If .the sliding member I61 is shifted to drive the gear IE5, the shaft I69 will be driven in one direction. If the member I61 is moved to engage the gear I66, the shaft I69 will be driven in the reverse direction.

As shown in Figure 6, the shifting of the clutch member I61 to selectively engage the gears I65 and I 56 to place the clutch in neutral position is accomplished by a yoke I16 on'a rock shaft I'II in the gear casing 35. A gear I12 On the shaft I1I meshes with a skew gear I13 on a shaft I'I I projecting through the front and rear end faces of the casing 35. Operating handles I15 are secured on the projecting ends of the shaft I1 1.

In order to lock the clutch I65 in neutral position, viz., with the member I61 out of engagement with both gears I65 and I66, the shaft I1 I has a notched locking plate I16 thereon adapted to receive a finger I11 in the notch thereof to prevent the shaft from rotating and cause the yoke I15 to hold the shifting member I61 in neutral position.

The finger I11 is keyed on a lock shaft IlII having a gear I18 thereon. A rack I 65 is actuated by the gear I18 and has a yoke I8I thereon acting on collars of a sliding gear hub I82 which is slidably keyed on the shaft 69 referred to hereinabove. A gear I63 secured to the hub I82 is meshed with a. gear 58% which is loose on the shaft 66, and this loose gear I84, in turn, is meshed with a gear I85 on the hub of the clutch gear I66. 7

Hand wheels I86 dispose in alignedoutward relationship from the hand wheels 1i on the end walls of the gear casing 35 are secured to the shaft 56 and are effective for rotating this shaft. Rotation of the shaft 69 will rotate the gear I83 and if this gear I83 is meshed with the gear I84 the gear I 85 will be driven to rotate the clutch gear I 66 and thereby actuate the shaft I69 man-' ually. However, the gear I83 is only meshed with the gear I85 when the clutch Hi l is locked in neutral position. This is accomplished by manual rocking of the lock shaft I16. levers I15 are tipped for shifting the yoke I16 to cause the clutch member I61 to engage a gear I65 or I66, the shaft I18 must first be rocked to unlocked position to unlock the finger I'I-1 permitting the yoke member I19 to move and at the same time the gear I16 on this lock shaft I19 will :be driven to move the rackIBB for sliding the hub I82 to move the gear I83 out of meshed engagement with the idler gear I84.

Therefore, manual actuation of'the shaft I 6.9 from a hand wheel I86 can only take place when the clutch is locked in neutral position. In this position the handles I15 are horizontal. I

As shown in Figure '12, the shaft I69 has a worm I86 thereon meshed with the worm wheelffi'I of another differential assembly I88. The worm wheel I81 is freely rotatable about the differential shaft I89 and is meshed with differential gears I95 on a spider 'IQI keyed to the differential shaft. These differential gears 90 are also meshed with a second worm wheel I92 freely rotatable around the differential shaft I89. A rapid traverse motor I93, for a purpose to be more fully hereinafter described, is meshed with the worm wheel I92.

The differential shaft I89 has a gear I94 keyed thereon and meshed with the gear I54;

As explained hereinabove, the tool carriage feed screw '32 will only be driven when the gear I 39 drives the ring gear I29 at a different rate than, or in an opposite direction to, the ring gear IZI and this can only be acomplished when the shaft I53 is driven to drive the spider M4 and add to the speed of the gear hub MI in driving the gear hub I43 or to reverse the direction of' rotation of the hub I 48 by driving the shaft M3 in the opposite direction. This shaft I43 can be driven at a desired selected speed by the speed changer devices or gear shifts interposed between the gear I52 and the reversing clutch I55. The. reversing clutch can drive the second differential 88 in opposite directions for rotating the shaft M3 at a speed relative to the speed of the gear I lIl determined by the setting of the gear changer and in a direction determined by the setting of the clutch. When the motor I93 is not ener- 'gized, it holds the worm wheel I92 against rotation so that rotation of the worm wheel I81 by the shaft I89 is effective to rotate the spider "ISI and drive the differential shaft I89 at the speed determined :by the shaft I69.

The feed screw 32 of the tool carriage is thus driven inwardly or outwardly, depending upon the position of the clutch I64 and at a speed ratio relative to the lathe-rotating speed which is selectively predetermined by the setting of the levers A, B and C of the gear-shifting mechanism. The main ring motor I3I thus not only. r drives the ring I6 to rotate the tool carriages,

but it also drives the feed screws of these tool carriages radially inward or radially outward at rates having selected ratio differentials from the rate of rotation of the lathe ring. Thus the lathe ring can be rotated very rapidly and the tool carriages can have a very slow radialfeed. Conversely, the lathe ring can be rotated at relatively slow speeds and the tool carriages can have relatively high radial feed speeds. g

If it is desired to rapidly change the radial positions of the tool carriageathe rapid traverse n" the tilt-ins motor I93 can be energized to drive the worm wheel I92 and cause rotation of the spider I9! for driving the differential shaft I89 at high speed. The rapid traverse motor will shift the carriages at a rapid rate radially inward or radially outward, even though the main lathe ring is not turning. The rapid traverse motor I93 also shown in Figures 1, 2 and 3, is a desirable electrical drive for quick setting of the radial positions of the tool carriages prior to lathecutting operations.

While only the drive for one feed screw 32 has been described and illustrated in Figure 12, it should be understood that the other feed screw 32 for the other tool carriage 21 is driven in an identical manner by merely duplicating the gear I50, shaft I5I, worm I52 and worm wheel I53. The second gear I50 will be diagonally opposite the illustrated gear I50 in Figure 12 meshed with the same row of teeth I291) on the movable ring gear I29. 7

Since it is sometimes desirable to manually adjust the radial positions of the tool carriages, the hand wheels I86 are provided to manually drive the shaft hereinabove, the clutch-actuating lever I15 must be in horizontal neutral position and the clutch must be locked in neutral position before these hand wheels I86 are effective. When the clutch is engaged, as when the levers I15 are tilted for radial infeed or outfeed of the tool carriages, the gear I83 is out of engagement with the gear I84 and the hand wheels are freely rotatable without driving the clutch. This safety feature is desirable so that the hand wheels I86 will not rotate when the tool carriages are being mechanically driven.

In order to maintain a constant speed relationship between the cutting tools and the surfaces being cut, the lathe ring is speeded up as the tool carriages are moved radially inward. For this purpose, the differential shaft I43 is coupled to a shaft I 95 (Figure 12) having a worm I96 on the end thereof driving a wheel I91 on a shaft I98 which shaft has a sliding gear I99 thereon actuated at I99a to be meshed with a ear 200 on a shaft 201. The shaft I extends into the top part of the casing as shown in Figure 6, and is connected through bevel gears 202 and 203 with a jack shaft 204 having a sprocket 205 on the end thereof driving a chain 206 and a sprocket 201 on a slip clutch 201a. secured to a rheostat control shaft 208. This rheostat control shaft 208 projects through the front end face of the casing and has a control knob 209 on the projecting end thereof. Rheostat arms 2!!! and 2 are secured on the shaft 208 in the casing 205 and act on rheostats 2I2 and 2I3, respectively. As will be hereinafter explained, setting of the knob 209 determines the initial speed of rotation of the lathe ring I6, and if the slide gear I99 is in engagement with the gear 290 to drive shafts 20I and 204, the sprocket chain 206 will drive the rheostat shaft 208 to increase the speed of the lathe ring as the tool carriages are driven inwardly at a rate determined by the diiferential shaft I43 which shaft also determines the rate of movement of the shaft I95 and the connecting shafts to the rheostat shaft 208. The arrangement is such that rotational speed of the lathe ring increases in proportion to the decrease in length of torque arm between the carriage tools and the center about which these tools are rotating.

In order to decrease the time for cutting sur- I69. However, as explained 18 faces which do not have continuous contact with the lathe tools for a complete 360 of rotation of these tools, the lathe ring is arranged so that it is speeded up whenever the tools move out of contact with the Work and is slowed down just immediately before the tools reccntact the work. This control is accomplished automatically by providing a gear 214 on the shaft I31. The gear 2I4, as shown in Figure 12, meshes with a gear 2I5 driving a, shaft 2I6 having a plate 2II on the end thereof for carrying replaceable templates correspondin to the shape of the surface being out. As shown in Figure 13, the plate 2|! has a template 2I1a thereon for the cutting of a cheek 256 of the crank shaft 25 described hereinabove. As indicated in dotted lines, the cheek 25c does not have the exact shape of the template and lies within the confines of the template in spaced relation from its edges. This oversized template shape is designed to cause a slowing down of the tool immediately before it hits the cheek surface so that the tool will not be subjected to a sudden shock. The template 2IIa, as indicated in Figure 13, has an inverted portion. This portion is provided when two tools 3I are being used since the lathe ring I6 must be slowed down twice and speeded up twice for a each revolution thereof when two tools are used.

The plate 2I'l is replaceable on the shaft 2I6 to carry different shaped templates corresponding with the type of Work surface to be acted on. The plate is of current-conducting material while the template insert 2I1a thereon is of insulating material. A fixed brush '2I8 acts on the plate and a movable brush 2I9 rides on and off the template 2111a. The brush 2I'9, as shown in Figure 12, is mounted on a carrier 220 threaded on the screw rod 22I driven through bevel gears 222 and 223 from the shaft I95. The handle 224 is provided for manual rotation of the rod '22I to initially set the radial position of the brush 2I9 with relation to the template 2IIa. The shaft I is driven when the tool carriages are fed radially as explained hereinabove, and drives the screw rod 22I to move the brush 2I9 in accordance with the radial position of the tools. As will be hereinafter more fully described, the electrical arrangement is such that the drivng of the lathe ring is speeded up whenever the brush 2| 9 rides out of contact with the template 2I1a and is slowed down whenever the brush rides on the template. This speeding up and slowing down control functions simultaneously with the radial speed-up of the tool ring as the tool carriages move radially inward.

From the above descriptions it will be understood that the motor I3I drives the main lathe ring I6 through a gear train including the fixed ring gear I27 on the main lathe ring. It will also be understood that the tool carriages are driven radially inward or radially outward by the same motor I3I driving the lathe ring I6 at a selected proportional speed determined by setting of gear shift rods A, B and C of a gear change mechanism and in a direction determined by a reversing clutch mechanism I64 actuated by a tilting rod I15. A rapid traverse motor I93 can be superimposed on the motor I3! for changing the radial position of the tool carriages as desired independently of the motor I 3|.

Automatic devices are provided for speeding up the rotation of the lathe ring as the tool carriages move radially inward for maintaining a constant surface speed relationship between the tools and the surface being acted on. Additional i9 automatic devices-areprovided for speeding up the rotation of the lathe ring whenever thetools leave contact with the Work piece, and for slowingdown rotation of l the lathe ring whenever the tools recontaet-thework piece.

The electrical controls In Figure 13 there is shown a simplified wiring diagram illustrating the electrical control for :salient parts of the apparatus. In :thisaswiring diagram, all circuit closing devices or switches except certain manually operable switches which will be specifically referredto, arerelayactuated and for convenience willbe referred to hereinafter as contacts. v

In general, the. control of the motor l3 lx'driving the main lathe ring it is effected through a motor-generator set,-and"the speed-of this main ring drive motor is controlled by voltage variation in thegenerator field and current variation in motor field. Lowspeedoperation of the lathe ring [6 is controlled by varyingthe voltage to :the generator field and higherlspeed operation of this lathe ringtis controlled by varying .thecurrent in the-motor field. Circuit meansare alsoprovided for alternately speeding up and slowing down-the Referring to Figure-13, an alternating current motor 225 is energized through conductors 226 of any suitable source of alternating-current supply. A manually operableswitch 22'! effects a closing or opening of the circuit-through control of a relay 228 governing the actuation of: archtactor arrangement generally indicated by numeral 228. Eye, commonshaft-connection 'the motor 22.5 drives a direct current exciter 230 which meets line conductors 23l:a-nd 232.

As a safety factor, the circuit through these line conductors is open until an'adequate'oil supply for the mechanism is provided. In the illustrated instance, line conductor 232 is open until the circuit is closed through conductors 233 and 234 by way of an oil pressure switch generally indicated by numeral23-5 associatedwith the main oil line 23$ leading to the ring bearing ll. Oil is supplied to the line 236' from the sump 1'25 through line231 by means of the oil pump I26 mechanically driven by the pump motor I21 energized by way of suitable conductors 238 from the aforesaid conductors 225. The conductors 238 are, of course, connected to the conductors 226 on the main motor side of the contact arrangement 229. Thus, when the control switch 221 is closed, the motor 225, exciter 23D and pump motor 121 are all in operation. However," the voltage supply from the exciter is not efiec'tive until the'oil pressure has reached a predetermined amount sufficient to close the oil pressure switch and thus complete the circuit through conductors-233 and A direct current generator 239, also mechanically driven by the main motor. 225through the commonshaft connection, supplies voltage by way of conductors 24!) and 241 to the armature of-the lathe ring drive motor l3l. shunted acros "the motor armature by conductor 2l2":is-.:.a dynamic 'brakin-gresistance 12 M). "The feedwcircuit from the generatOF'ZBQ to the motor .l3l ,is controlled by a'contact 2H governing the :circuit through conductor 24!, and the-dynamic braking circuit is-controlled by a contact "2E5 governing the energization of conductor 22532.

The contacts 254' and "245 are simultaneously actuated-so thatwhen'the circuit is-closed-between the generator and themotor, contact 24il opens the dynamic braking circuit, and whenthe generator supply circuit is opened-by'cont'actor 2442',- contact 245 closes the dynamic lora'kir'ig cir cuit. It will'therefore be appreciated'that when it-is desired to stop operation whenthe generatorsupply circuit is open, the-lathe ring drive motor l Si willtend to function as a generator and the counterelectromotive' force set up' by the motor will energize the dynamic braking circuit to effect very quick stopping. I

The speed of the motor I3! is controlled'byrheostats 2l2-andf2=l3' above mentioned. The

'rheostat'2l2 is a motor field rheostat andthe 'rheostat' 21*3 is a potentiometer rheostat controlling the-voltage to the generator field. The

arms 220 and 2|l,,o-ftheseyrhmStats are on the same shaft 283, :as explained above. Thi's" arrangement provides the constant cutt'ing'speed in linear'f-eetper minuteias the cutting tool or tools reduces the diameter-either Work. The :rheostatshafti'iiiilpan'be adjusted manually, regardlessof the mechanical ,drive connection, by means of the :slip ;-c-lutch 519%.

these 'rheostats areblanked'out. As shown, rheostat 212 embodies-a solid conductor portion-2% and a resistance portion 241, while the rheostat 2E3 includes a resistance portion 248 anda solid conductor portion 249, the .resistance portio'n 2 3,8 being substantially equalinarcuatelength to the solidlcon'ducting portion 245, and the solid conducting portion ,214'9 being similarly equal to the resistanceportion' 2 51. The arrangement is such that, assuming'the rheosta't armsiare operated clockwise, low speed variationsgare effected'by the;p0rtion 248 of thepotentiometer rheos'tat 2L3 tor T253 t0 .line conductor 232.

through the generator field, and higher speeds are selectively acquired by means ofthe resist-ancelportion 24.1 of the motor fieldrrheostat Theresistance element of themotorfieldrheo stat 2124s ,connectedto .line conductor 1231 by conductor .250 at one end and atthe, other end rheosiat '2 .isconnecte-zlto line conductor .23l byl-conductorfzfifi .at-..one end-and at; the other end through,conductoriE] toline conductor 232, nor.-

maillyl-open contact ze'ideontrolling the energizetionof this portion of the circuit. The-arm of this. rheostat is connected by. conduct-0rd 5.9 cmbodying a normally closed contact 250,- and then by way of conductor .26! .to.a{reversing switch generally indicatedby numeral 282 and-to one side .of thefield 2 6,3iof the generator ziifi; The

other side of the {generator field is connected through. the reversing. switch anda conductorifi l to the positive (line conductorr23l, vGert-ainvoltage controls are incorporated in the generator field circuit to establish fixed limits of control 7 Since bothit'he rheostat armsmove together, certain portions of 

